EP3692199B1

EP3692199B1 - Consumer product component

Info

Publication number: EP3692199B1
Application number: EP18792527.6A
Authority: EP
Inventors: Geoffrey William Collins; Eric Mariani; Nicolas LANDSPURG
Original assignee: Glatfelter Holding Switzerland AG
Current assignee: Glatfelter Holding Switzerland AG
Priority date: 2017-10-06
Filing date: 2018-10-05
Publication date: 2023-10-04
Anticipated expiration: 2038-10-05
Also published as: DK201770761A1; ES2965446T3; EP3692199A1; WO2019069283A1; FI3692199T3; DK179815B1; US20200255991A1

Description

FIELD OF THE INVENTION

The present invention relates to a non-woven fabric, more specifically to a non-woven fabric having certain strength and elongation properties.

BACKGROUND OF THE INVENTION

Synthetic fabric, and especially lightweight fabric, is used in a large variety of applications.
By being lightweight, the fabric may be made in a cost-efficient way concerning material usage, material costs, and transportation costs. Further, synthetic fabric enables thin and light composite products.
Applications foreseen by the present disclosure include the use of the non-woven fabric as a component in baby diapers, closure mechanisms in diapers, adult incontinence products, feminine hygiene products, and in the healthcare industry in general. Said products may all require some degree of stretch or elongation for use. In the following, the use of the fabric as a component in diapers is considered. Nowadays, diapers are commonly made of a synthetic fabric due to the reduced costs and improved properties compared to natural materials. However, diapers need to meet certain requirements concerning feel and strength. The feel is highly important due to the peculiar use, whereas the strength is important due to the wear and handling. Today, diapers are made in different designs, where especially the closure mechanism relies on different techniques depending on the make. For example, the closure mechanism may rely on hook and loop fasteners attaching ears of the diaper onto the waist of said diaper. The ears are the tabs on the side of the diaper having hook and loop fasteners or similar non-permanent fixing to close and adjust the diaper fitting. Typically, the hook and loop fasteners are adjusted according to the size of the user, e.g. through the ears comprising hooks and the waistband comprising a band of loops, whereby the ears may be attached any place on said waistband. In another configuration, the ears are stretchable/flexible ("stretch-ears"), whereby an elastic or recovery effect arise, said recovery effect improving the closure and fit. It should be noted that not all diaper products necessarily comprise fasteners arranged on the waistband (sometimes referred to as the landing zone). Moreover, a waistband may not even be present, but instead be embodied as an integral part of the diaper. In some products, the landing zone may be specifically engineered and may be of another substrate added as a layer to the remaining assemble.
However, stretchable ears impose certain limitations to the fabric being stretched, most importantly its elongation properties. For this reason, different types of fabric have been employed in an attempt to balance the required strength and elongation. A desire exists to replace the types of fabric used nowadays with a fabric comprising optimised strength and elongation properties and preferably accompanied by an improved softness without affecting the cost.
WO 99/02766 A1 teaches how to increase the filling factor of a fibre mat by producing it from a mineral fibre-based fibre structure with a bimodal fibre length distribution. This means that one group of fibres will be longer than the other, whereby the filling capacity is increased and a firm surface is obtained. This effect is further enhanced by the random relative orientation of the fibres.
EP 0511388 A1 discloses a leather-touch fabric made in a two-layer structure consisting of an upright hair-like raised fibre layer and a down-like raised fibre layer. The artificial leather fabric is knitted from polyester fibres, where the hair-like raised fibres, also called guard fibres, are longer than the down-like underfur which is treated to have a shorter, uniform height.
WO 2014/076353 teaches a composite material comprising a thermoplastic matrix material and two groups of fibres that may be distinguished by their physical properties. The length weighted average length of the first group of fibres is less than 0.9 times the length weighted average length of the second group of fibres. The composite material is made through heat treatment leading to partially melting of the matrix material, whereby the material mixture is held together.
EP 1091042 A1 discloses a water-decomposable fibrous sheet comprising primary fibres of a predetermined fibre length, between 1.8 mm and 10 mm, and microfibers extending from those primary fibres. The fibres are made from rayon which has been treated to become fibrillated rayon, i.e. the rayon frays, whereby microfibers come partially loose from the primary fibre and extend away from it. These microfibers allow bonding of adjacent primary fibres as they tangle with each other. The fibrous sheets are consolidated through a process of compressing the fibres, while they are heated and wetted, whereby hydrogen bonds are created.

GENERAL DESCRIPTION

An object of the present invention is to solve some of the above-mentioned problems.
More specifically, the present invention discloses a non-woven fabric according to claim 1. This non-woven fabric comprises a plurality of textile fibres, wherein said plurality of fibres comprises fibres that have been selected from two groups of fibres. The first group of fibres comprises multiple fibres having a first average length, and the second group of fibres comprises multiple fibres having a second average length, the first average length being shorter than the second average length. Further, the fibres of the first group of fibres have a first length variance being greater than a second length variance of the fibres of the second group of fibres and said average length of the fibres of the second group is above 30 mm. Further, the invention discloses a method of making a non-woven fabric according to claim 14. This method comprises selecting fibres from two groups of fibres; a first group of fibres comprising multiple fibres having a first average length and a first length variance, and a second group of fibres comprising multiple fibres having a second average length and a second length variance, where the first average length is shorter than said second average length, and combining said fibres by hydroentanglement, characterized in that the first length variance is greater than said second length variance and said average length of the fibres of the second group of fibres is above 30 mm.
Preferably, the non-woven fabric is a lightweight fabric. By being a lightweight fabric, comparison is drawn to a fabric of identical use, quality, or function, but where the lightweight fabric is lighter. In the present context, a fabric is considered lightweight if it weighs less than 30 grams per square meter (gsm, g/m²). The non-woven fabric is a non-woven fabric made from hydroentanglement, also known as spunlacing.
By a plurality of textile fibres is meant that multiple textile fibres are combined in a plurality, where a part of said textile fibres may be identical/indistinguishable within the plurality.
The non-woven fabric comprises at least two groups of fibres, whereby it should be understood that said groups comprise different properties. Said properties may be differences in regard to average length, variance, or inherent material properties. A group may comprise a blend of distinguishable fibres, such that fibres made of different materials or properties are blended into a single group. For example, one group may comprise polyester (PES) fibres and polypropylene (PP) fibres blended into a blend. When referring to polyester in this document, it should be understood that polyester is a family covering multiple polymers which may be suitable in the present invention. An example of a polymer being classified as a polyester is polyethylene terephthalate (PET) which is a preferred type of polyester in the present invention. The relative amounts of PES fibres and PP fibres may vary between the groups, just as the average length or length variance may vary between the groups. In the case of a blend, the fibres constituting the blend may have been blended prior to selecting the fibres to constitute the fabric. Thereby, the blend may be provided from external sources, whereby the production line is simplified.
By a first group of fibres comprising multiple fibres having a first average length being shorter than a second average length of fibres within a second group of fibres, is meant that the fibres being part of the first group are on average shorter than the fibres within the second group of fibres. The average may be the mean or more specifically the geometric mean. The maximum length of any given fibre within the first group of fibres, i.e. any fibre contributing to the average length of the fibres in the first group, may be equal to, or shorter than, the average length of fibres within the second group of fibres. In other words, the maximum length of a given fibre within the first group may be said to be limited to the average length of the fibres within the second group.
Thereby, the elongation properties of the fabric is changed in respect of the cross direction of the fabric, whilst maintaining almost unchanged strength in the longitudinal direction at a low basis weight. The elongation properties include a controlled reduction in the cross-directional tensile strength and a corresponding increase in cross-directional elongation, whilst still providing enough cover and longitudinal direction strength for the material to be made and formed in industrial processes. Thus, the extension profile may be said to be engineered when using fibres of different average lengths in a fabric as disclosed. Further, the possibility of controlling the average lengths of fibres through the right selection of groups of fibres provides a possibility of engineering the strength in detail. More specifically, according to the present invention, a weakness is engineered in the cross direction, whereby the maximum elongation length in said cross direction is increased compared to a conventional and comparable fabric not comprising groups of fibres selected according to the invention.
By a cross direction and a longitudinal direction is meant directions relative to the machine preparing the fabric using hydroentanglement. Said directions are relevant since the industrial process of making non-woven fabric using hydroentanglement is conducted on a conveyor belt. When making a non-woven fabric using hydroentanglement, the cards preparing and laying the fibres prior to hydroentanglement are usually in line with the rest of the machinery, i.e. the fibres are laid in a fibrous web on the conveyor belt moving at a given speed into the hydroentanglement section. This fact causes the fibres to be oriented primarily in the longitudinal direction, also known as machine direction, relative to the travelling direction of the conveyor belt. The processes within the card itself may also cause the fibres to be oriented primarily in the longitudinal direction. Thereby, the strength in the longitudinal direction is greater than in the cross direction, said cross direction being perpendicular to the longitudinal direction. Thus, the cross direction may also be named the transverse direction. The longitudinal strength is greater since friction between fibres being oriented primarily in the same direction is greater.
The cross-directional strength of the fabric according to the invention is reduced due to the introduction of a first group of fibres comprising multiple fibres having a first average length being shorter than the second average length of the fibres in the second group of fibres. The difference of fibre lengths within the fabric causes the reduction of cross-directional strength since it is the friction between individual fibres that characterises a non-woven fabric, and a reduced length of a part of the fibres causes said friction to be reduced, in turn causing the strength to be reduced. The specific average lengths used to engineer the desired properties of the fabric according to the invention depend on the end use of said fabric.
In an embodiment, the fibres of the first group of fibres may have a first length variance being greater than a second length variance of the fibres of the second group of fibres.
By a first group of fibres comprising multiple fibres having a first average variance being greater than the second average variance of the fibres of the second group of fibres, is meant that from the plurality of fibres constituting the fabric, the fibres being part of the first group of fibres have on average a greater length variance than the length variance of the fibres being part of the second group of the fibres. By variance is meant the statistical term for the expectation of the squared deviation of a random variable from its mean. Instead of variance, the variation may be described through the standard deviation, the standard deviation being the square root of the variance.
The length of the fibres in the first group of fibres and the length of the fibres in the second group of fibres may be normally (Gaussian) distributed. In other words, the length of the fibres may be normally distributed around a mean value, the mean value being the average length of the fibres within the relevant group. In other words, the length of the fibres within each group may constitute a normal distribution. The standard deviation deduced from the normal distribution of the lengths of the fibres of the first group of fibres (i.e. the first normal distribution) may be broader than the standard deviation deduced from the normal distribution of the lengths of the fibres of the second group of fibres (i.e. the second normal distribution). Further, the first and second normal distributions may be separated by more than two standard deviations related to the second normal distribution. Thereby, the mean lengths of the fibres of the first and second group of fibres are significantly separated. In other words, the mean of the normally distributed lengths of the first group of fibres is separated from the mean of the normally distributed lengths of the second group of fibres by at least two standard deviations. It is noted that reducing the variance of a population reduces the width of the corresponding normal distribution. Thus, the first group of fibres may have a broader normal distribution than the normal distribution of the second group. For this reason, it was specified above that the separation of at least two standard deviations is related to the second normal distribution in regard to the standard deviation.
Thereby, a second possibility of engineering the properties, including the strength, of the non-woven fabric according to the invention is attained. Further, through a difference in length variances (or a separation of the first and second normal distribution, if the lengths are normally distributed), the at least two groups of fibres are increasingly distinguishable in the fabric.
In an embodiment, the first group of fibres may comprise a blend of polyester (PES) fibres and polypropylene fibres (PP).
The first group of fibres may also be said to be a blend of fibres comprising PES fibres and PP fibres, such that said first group of fibres solely comprises PES fibres and PP fibres. However, fibres made from other materials than PES and PP may be included in the first group as well.
The fibres within the second group of fibres may likewise be embodied in blends.
Thereby, the first group of fibres is ensured to encompass inherent properties of PES and PP.
In an embodiment, the ratio between PES fibres and PP fibres in the first group of fibres is between 1:0 (PES:PP) and 0:1 (PES:PP).
Thereby, the first group of fibres may comprise anything between 100 % PES fibres and 0 % PP fibres (1:0) and 0 % PES fibres and 100 % PP fibres (0:1). However, preferred ratios are 1:1 (PES:PP, e.g. 50 % PES fibres and 50 % PP fibres), or 45 % PES fibres and 55 % PP fibres, or 20 % PES fibres and 80 % PP fibres, or purely PP fibres, i.e. 100 % PP fibres. Likewise, said preferred ratios further include the corresponding ratios of 45 % PP fibres and 55 % PES fibres, or 20 % PP fibres and 80 PES fibres, or purely PES fibres, i.e. 100 % PES fibres.
In an embodiment, the first group of fibres may constitute 50 % of the fabric.
Thereby, half of the fabric is composed of fibres belonging to the first group, i.e. half of the fibres constituting the fabric is on average shorter than the other half of fibres. However, other percentages are foreseen within the present invention.
In an embodiment, the second group of fibres within the fabric may comprise 50 % PES fibres and 50 % PP fibres.
Thereby, the fabric comprises PES fibres and PP fibres in varying ratios and varying average lengths. Thus, the inherent properties of PES and PP are utilised, but the use of different average lengths allows engineering of the elongation properties.
In an embodiment, the fibres of the first group of fibres may have an average length below 30 mm and a length variance above 5 mm.
In an embodiment, the fibres of the second group of fibres may have an average length above 30 mm and a length variance below 5 mm.
Thereby, the average length of fibres within the first group is shorter than the average length of fibres within the second group of fibres. Likewise, the variance in length is greater for the fibres within the first group than for the fibres within the second group.
In an embodiment, the fabric is a non-woven fabric.
By a non-woven fabric is meant a fabric wherein the individual fibres are bonded together in a random manner, e.g. through entanglement and frictional forces.
In an embodiment, the selection may be made among PES fibres, PET, and PP fibres.
Thereby, the fabric benefits from the inherent properties of PES, PET, and PP which may all be considered textile fibres. More specifically, the mentioned textile fibres have a low density compared to other textile fibres. Thereby, more textile fibres may be present in the fabric at a given basis weight. Further, if a given number of fibres is required to make a coherent fibrous web, the resulting fibrous web is lighter than when made from denser fibres.
In an embodiment, PP fibres may constitute at least 50 % of said fabric.
Thereby, a majority of the fabric is PP. The amount of PP is essential for sonic bonding the fabric in a possible subsequent step since less energy is required to cause bonding between PP fibres than between PET fibres. Thereby, sonic bonding machinery may be run faster.
In an embodiment, the density of the fibres used within the fabric according to the invention may be between 1.3 dtex and 1.7 dtex.
However, the use of finer (< 1.3 dtex) fibres or coarser (> 1.7 dtex) fibres are foreseen within the present invention. For example, use of finer or coarser fibres may be envisaged as part of the product engineering in one or more of the groups of fibres. Further, the fibres may comprise varying cross sections. For example, the cross section of the fibres may be round, flat, trilobal, multilobal, triangular, hollow, solid.
Thereby, the low density of the fibres adds to the lightweight properties of the fabric.
Further, the low density of the fibres allows the basis weight of the fabric to be reduced in case a fixed number of fibres is needed to form a fabric having the desired strength, opacity, softness, and volume. By density is meant the yarn count expressed in terms of mass per unit length. In the present case, the unit used is dtex which is equal to the number of grams per 10,000 m.
In an embodiment, the basis weight of the fabric may be between 15 gsm and 35 gsm, or between 20 gsm and 30 gsm.
Thereby, the fabric is considered lightweight since fabric weighing below approximately 30 gsm is generally considered lightweight in the industry.
In an embodiment, the non-woven fabric is made using hydroentanglement.
Hydroentanglement is a fabrication technique wherein the individual fibres are entangled using high-pressure water jets. Spunlacing is another word for hydroentanglement. When fabricating a non-woven fabric using hydroentanglement, a plurality of non-entangled individual fibres is arranged in a fibrous web followed by the introduction of multiple high-pressure waterjets, said water jets penetrating the fibrous web and causing entanglement and thereby (mutual) physical bonding of the textile fibres. Thereby, the entanglement of textile fibres creates a non-woven fabric. The fibrous web may be formed using at least one card, but may also be formed by other means. Hydroentanglement is commonly employed to non-woven fabric having a relatively low weight due to the limitations set by the use of water jets. A relatively low weight may be less than 100 gsm (grams per square meter, g/m²).
Thereby, benefits, mainly the look and feel, from hydroentanglement are achieved.
Further, hydroentanglement provides the possibility of making a fabric lightweight.
In an embodiment, the fabric may be provided with a stretch engine also called a flexible element.
In order to use the fabric in diapers, it may be advantageous to equip said diapers with closure mechanisms being flexible. Thereby, the waistband keeping the diaper in place is always tightened around the waist of the user. Similar flexible behaviour may be wanted or needed in other uses as well. By a stretch engine is meant a flexible element capable of extending and recovering without deformation, preferably a type of plastic, such as polyethylene (PE). For example, the stretch engine may be a stretch-film laminated onto the fabric by means of glue or heat application, a stretch adhesive applied to the substrate, or any other element capable of providing a stretch and recovery to the fabric according to the invention. Preferably, the flexible element is applied to the fabric in an almost relaxed state of said fabric, where a relaxed state is a state wherein no external forces are applied. By being in an almost relaxed state during the application process, it is ensured that the flexible element and the fabric are smooth and non-deformed. Thereby, when pulling the combined fabric and flexible element in opposite directions, the flexible element extends and additionally provides an opposite-directed force aiming to revert the extended flexible element and fabric to the original relaxed state. Thus, the flexible element provides a recovery effect to the fabric. In other words, the flexible element may be regarded a stretch-and-recovery-element. However, in such use, the fabric has to comprise beneficial elongation properties in the cross direction, said beneficial elongation properties including a low modulus at the relevant part of the stress-strain curve compared to the longitudinal direction. The strength of the flexible element limits the maximum elongation of the fabric, whereby said maximum elongation of the fabric is limited to the maximum elongation of the flexible element. Therefore, the strength of the fabric should be sufficient to withstand tearing for the entire elongation range set by the flexible element. Preferable elongation properties and tensile strengths are found in a fabric according to the invention.

SHORT LIST OF THE DRAWINGS

In the following, example embodiments are described according to the invention, where

Fig. 1 illustrates a diaper comprising a fabric according to the invention.
Fig. 2 illustrates the selection process of selecting fibres constituting a fabric according to the invention.
Fig. 3 illustrates a non-woven fabric according to the invention.
Fig. 4 illustrates the process of making a fabric according to the invention.
Fig. 5 illustrates a first and a second normal distribution related to the invention.

DETAILED DESCRIPTION OF DRAWINGS

In the following the invention is described in detail through embodiments. Fig. 1 illustrates a conceptual diaper 10 comprising a non-woven fabric 100 according to the invention.
The diaper 10 comprises a front 11, a back 12, and an intermediate section 13, said intermediate section 13 comprising an absorbing pad 14. The back 12 comprises a set of ears 15, said ears 15 further comprising a first attachment means 16. Said first attachment means 16 is for engaging with a second attachment means 17 arranged on the front 11. Preferably, the attachment means 16,17 are hook-and-loop fasteners, i.e. the first attachment means 16 may be a plurality of hooks, and the second attachment means 17 may be a plurality of loops. Alternatively, the plurality of loops is omitted since a fabric as disclosed inherently comprises suitable loops for engaging with the hooks in the first attachment means 16. The fabric 100 is at least embodied in the ears 15, but may be embodied in the entire diaper 10. Further, at least the ears 15 are equipped with a flexible element (not shown) for providing a stretch and recovery effect of the ears 15. When putting on the diaper 10, the first attachment means 16 engages with the second attachment means 17, such that a closure around the waist of the wearer is provided. The presence of the fabric 100 according to the invention in the ears 15 provides an enhanced flexibility in combination with the flexible element since said fabric 100 comprises advantageous elongation properties in the cross direction, and said flexible element contributes to a recovery effect. Said cross direction of the fabric 100 is arranged such that the advantageous elongation properties are parallel to the waist of the diaper 10 and the wearer. The advantageous elongation properties are mainly an ability to elongate a greater distance in the cross direction without tearing compared to the longitudinal direction in the same fabric or in a comparable fabric without engineered elongation properties.
Fig. 2a illustrates the selection process when making a fabric 100 according to the invention. The selection S in the present embodiment comprises a first group of fibres F and a second group of fibres X, said second group X comprising a plurality of a first fibre 131 (solid) and a plurality of a second fibre 132 (dashed). Said first group F comprises a plurality of polyester (PES) fibres 111 (solid) and a plurality of polypropylene (PP) fibres 112 (dashed). The ratio of PES fibres 111 to PP fibres 112 may be 1:1, i.e. the first group F comprises 50 % PES fibres 111 and 50 % PP fibres 112. However, the ratio between PES fibres 111 and PP fibres 112 may vary from 1:0 and 0:1 according to the invention. It should be noted how the depicted PES fibres 111 and PP fibres 112 within the first group F are shorter than the depicted first 131 and second fibres 132 within the second group X. Thereby, the depicted selection S is in accordance with the invention.. The group X may be seen as a blend of multiple different fibres. Nevertheless, the average length of the fibres within the second group X should be longer than the average length of fibres within the first group F. Further, the length variance of the fibres within the second group X should be smaller than the length variance of the fibres within the first group F according to an embodiment of the invention.
Fig. 2b illustrates a conceptual depiction of the average lengths and length variances of fibres within the selection S. A first average length A1 relates to the average length of fibres within the first group F, whereas a second average length A2 relates to the average length of fibres within the second group X. Likewise, a first length variance V1 relates to the length variance of the fibres within the first group F, whereas a second length variance V2 relates to the length variance of the fibres within the second group X. As shown, the first average length A1 is shorter than the second average length A2 (i.e. A1<A2). Likewise, it is shown how the first length variance V1 is greater than the second length variance V2 (i.e. V1>V2). The maximum length of a given fibre within the first group F may be equal to or less than the second average length A2 of fibres within the second group X.
Fig. 3 illustrates a non-woven fabric 100 according to the invention. A longitudinal direction L and a cross direction C have been indicated. A first zoom Z illustrates microscopic details of the fabric 100. More specifically, the first zoom Z illustrates a plurality of fibres, said plurality of fibres constituting the selection S of fibres according to the invention. For details regarding the constituents of said selection S, see Fig. 2 and the corresponding description. It should be noted how a majority of the plurality of fibres in the selection S are arranged in parallel to the longitudinal direction L. Said longitudinal direction L is also known as the machine direction. When laying a fibrous web of fibres to be bonded in a fabric 100 as disclosed, said fibres are likely to be arranged in said longitudinal direction L. The arrangement of fibres causes the fabric 100 to have a higher tensile strength in the longitudinal direction L than in the cross direction C. Further, the arrangement of the fibres effect the elongation properties of the fabric. The presence of a selection S according to the invention provides the ability to engineer the elongation properties in both the longitudinal direction L and in the cross direction C through the fibres comprising different average lengths and variances. Further, the fabrication technique arranging the fibres primarily in the longitudinal direction provides a second possibility of engineering the elongation properties. The fibres, or at least a part of the fibres, constituting the selection S may be textured or crimped.
In an embodiment, at least one side of the fabric 100 is provided with a flexible element 200. Preferably, said flexible element 200 is a stretch-film laminated onto a surface of the fabric 100 through glue, heat application, or similar methods for bonding the materials. However, the flexible element 200 may likewise be an adhesive prodiving similar stretch and recovery properties. The flexible element 200 is capable of a reversible extension when exposed to opposite-directed external forces, i.e. said flexible element inherently comprises a recovery effect. When the flexible element 200 is combined with the fabric 100, said recovery effect ensures that said fabric 100 may return from an elongated state to its relaxed state when no opposite-directed external forces are applied.
A first set of arrows 1a, 1b indicates a first pull in the cross direction C. Said first pull may be said to be opposite-directed external forces, i.e. the pull aims to extend the fabric 100 in the cross direction C. Likewise, a second set of arrows 2a,2b indicates a second pull in the longitudinal direction L. The combination of fibres within the selection S according to the invention gives the fabric 100 engineered elongation properties, including an altered stress/strain curve, compared to a selection without a selection and combination of fibres as disclosed. Further, said engineered elongation properties include a reduced tensile strength and a greater maximum elongation length which is desired in the intended use of the fabric although other uses are foreseen. Further, the selection S causes the longitudinal tensile strength to be reduced compared to a selection without a selection and combination of fibres as disclosed. The increased maximum elongation length compared to a conventional and comparable fabric may be desired when a highly flexible and stretchable fabric is needed, such as in use in diapers.
Fig. 4 illustrates the process of making a non-woven fabric 100 according to the invention. Fig. 4a
illustrates a side view of the process, whereas Fig. 4b illustrates a top view of the embodiment shown in Fig. 4a. A card 20 is provided with a selection S of fibres according to the invention. Said selection S comprises a first group F and a second group X of fibres. Said second group X may comprise multiple fibres made of different materials or having different average lengths and length variances. However, according to the invention, the first group F comprises a plurality of fibres having an average length being shorter than the average length of the fibres within the second group X. Further, said fibres within the first group F may have a length variance being greater than the length variance of the fibres within the second group X. The card 20 lays a fibrous web 21 comprising the fibres within the selection S on a conveyor belt 22, said conveyor belt 22 moving the fibrous web 21 into a hydroentanglement station 31. The direction of the conveyor belt 22 is indicated by the arrow 29. The hydroentanglement station 31 applies a plurality of waterjets 32 onto the fibrous web 21, whereby the fibres within said fibrous web 21 are bonded/entangled. The end product of the process is a fabric 100 according to the invention which is bonded using hydroentanglement. Further processing may include providing the fabric 100 with a flexible element or shaping of the fabric 100 into a desired product. Said shaping procedure may include the use of sonic bonding.
It should be understood, that the above-disclosed process of making a fabric according to the invention may include for example multiple cards that may be used each providing different groups of fibres, just as other aspects may vary in production.
Fig. 5 illustrates a first N1 and a second N2 normal distribution of the lengths related to the first group of fibres and the second group of fibres, respectively. The first standard deviation D1 and the second standard deviation D2 are indicated as well, the first standard deviation D1 relating to the first group of fibres, and the second standard deviation D2 relating to the second group of fibres. From the size of the standard deviations, it is seen how the first group of fibres (resembled by the first normal distribution N1) has a greater variance than the fibres of the second group of fibres (resembled by the second normal distribution N2) according to an embodiment of the invention. The skilled person is aware that the standard deviation is related to the variance through the standard deviation being the square root of the variance. In an embodiment, at least the first normal distribution N1 is skewed, and especially the first normal distribution N1 may be negatively (left) skewed.
Further, it is noticed how the mean M2 of the second normal distribution N1 is lower (see orientation of axis K, said axis denoting the length of fibres within the first and second group of fibres) than the mean M1 of the first normal distribution N1 according to a preferred embodiment of the invention. The nomination of "mean" instead of average length as used above is used in accordance with common nomenclature in statistics.
The separation of the first N1 and second N2 normal distributions may be described through the size of the first standard deviation D1. In an embodiment of the invention, the separation of the two normal distributions may be at least two standard deviations, where said at least two standard deviations are measured using the second standard deviation D2. This minimum separation is indicated using the juxtaposed set of arrows D2', each of said arrows being equal in size to the second standard deviation D2.

REFERENCE NUMBERS

A1: First average length
A2: Second average length
C: Cross direction
D1: First standard deviation
D2: Second standard deviation
D2': Minimum separation
F: First group of fibres
K: Axis
L: Longitudinal direction
M1: Mean of the first normal distribution N1
M2: Mean of the second normal distribution N2
N1: First normal distribution
N2: Second normal distribution
S: Selection
V1: First length variance
V1: Second length variance
X: Second group of fibres
Z: Zoom
1a: First pull
1b: First pull
2a: Second pull
2b: Second pull
10: Diaper
11: Front
12: Back
13: Intermediate section
14: Absorbing pad
15: Ears
16: First attachment means
17: Second attachment means
20: Card
21: Fibrous web
22: Conveyor belt
29: Moving direction of conveyor belt 22
31: Hydroentanglement station
32: Water jets
100: Non-woven fabric
111: PES fibres
112: PP fibres
131: First fibres
132: Second fibres
200: Flexible element

Claims

A non-woven fabric comprising a plurality of textile fibres, said plurality of fibres comprising fibres that have been selected from two groups of fibres;
- a first group of fibres (F) comprising multiple fibres having a first average length (A1), and

- a second group of fibres (X) comprising multiple fibres having a second average length (A2), where

said first average length (A1) is shorter than said second average length (A2),

wherein the fibres of said fabric are oriented primarily in the same direction,

characterised in that the fibres of the first group of fibres (F) have a first length variance (V1) being greater than a second length variance (V2) of the fibres of the second group of fibres (X), and that said average length (A2) of the fibers of said second group of fibres (X) is above 30 mm.
A non-woven
fabric according to claim 1, wherein the first group of fibres comprises a blend of polyester (PES) fibres and polypropylene (PP) fibres.
A non-woven
fabric according to claim 2, wherein the ratio between PES fibres and PP fibres in the first group of fibres is between 1:0 and 0:1.
A non-woven
fabric according to any of the preceding claims, wherein the first group of fibres constitutes 50 % of the fabric.
A non-woven
fabric according to any of the preceding claims, wherein the second group of fibres comprises 50 % PET fibres and 50 % PP fibres.
A non-woven
fabric according to any of the preceding claims, wherein the fibres of the first group of fibres have an average length of 28.5 mm and a length variance of 9.5 mm.
A non-woven
fabric according to any of the preceding claims, wherein the fibres of the second group of fibres have an average length of 39 mm and a length variance below 5 mm.
A non-woven
fabric according to any of the preceding claims, wherein the plurality of fibres is chosen among among PES fibres, PET fibres, and PP fibres.
A non-woven
fabric according to any of the preceding claims, wherein PP fibres constitute at least 50 % of said Z non-woven fabric.
A non-woven
fabric according to any of the preceding claims, wherein the density of the fibres used within the fabric is between 1.3 dtex and 1.7 dtex.
A non-woven
fabric according to any of the preceding claims, wherein the basis weight of said non-woven fabric is between 15 gsm and 35 gsm, or between 20 gsm and 30 gsm.
A non-woven
fabric according to any of the preceding claims, wherein said fabric is made using hydroentanglement.
A non-woven
fabric according to any of the preceding claims, wherein said non-woven fabric is provided with
a flexible element.
A method of making a non-woven fabric comprising a plurality of textile fibres, said method comprising selecting fibres from two groups of fibres;
- a first group of fibres (F) comprising multiple fibres having a first average length (A1) and a first length variance (V1), and

- a second group of fibres (X) comprising multiple fibres having a second average length (A2) and a second length variance (V2),
where the first average length (A1) is shorter than said second average length (A2), and combining said fibres by hydroentanglement, characterised in that the first length variance (V1) is greater than said second length variance (V2), and that said average length (A2) of the fibers of said second group of fibres (X) is above 30 mm.